title: Phoneutria spider toxins block ischemia-induced glutamate release and neuronal death of cell layers of the retina.
abstract: OBJECTIVE
  To investigate the effect of calcium channel blockers, spider toxins, on cell viability and the glutamate content of ischemic retinal slices.
  
  
  METHODS
  Rat retinal slices were subjected to ischemia via exposure to oxygen-deprived low-glucose medium for 45 minutes. Slices were either treated or not treated with the toxins PhTx3, Tx3-3, and Tx3-4. After oxygen-deprived low-glucose insult, glutamate content and cell viability were assessed in the slices by confocal and optical microscopy.
  
  
  RESULTS
  In the retinal ischemic slices that were treated with PhTx3, Tx3-3, and Tx3-4, confocal imaging showed a decrease in cell death of 79.5 ± 3.1%, 75.5 ± 5.8%, and 61 ± 3.8%, respectively. Neuroprotective effects were also observed 15, 30, 60, and 90 minutes after the onset of the retinal ischemic injury. As a result of the ischemia, glutamate increased from 6.2 ± 1.0 nMol/mg protein to 13.2 ± 1.0 nMol/mg protein and was inhibited by PhTx3, Tx3-3, and Tx3-4 to 8.6 ± 0.7, 8.8 ± 0.9, and 7.4 ± 0.8 nMol/mg protein, respectively. Histologic analysis of the live cells in the outer, inner, and ganglion cell layers of the ischemic slices showed a considerable reduction in cell death by the toxin treatment.
  
  
  CONCLUSIONS
  Spider toxins reduced glutamate content and cell death of retinal ischemic slices.
authors.affiliation: Graduation Course in Biomedicine, Santa Casa Hospital, Belo Horizonte, Minas Gerais, Brazil.
authors.forename: Rafael Mourão
authors.initials: RM
authors.lastname: Agostini
authors.forename: Ana Cristina
authors.initials: AC
authors.lastname: do Nascimento Pinheiro
authors.forename: Nancy Scardua
authors.initials: NS
authors.lastname: Binda
authors.forename: Marco Aurélio
authors.initials: MA
authors.lastname: Romano Silva
authors.forename: Marta
authors.initials: M
authors.lastname: do Nascimento Cordeiro
authors.forename: Michael
authors.initials: M
authors.lastname: Richardson
authors.forename: André Luiz
authors.initials: AL
authors.lastname: Sena Guimarães
authors.forename: Marcus Vinicius
authors.initials: MV
authors.lastname: Gomez
mesh_terms: D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology; D016923:Cell Death / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D018698:Glutamic Acid / Q000378:metabolism*; D018613:Microscopy, Confocal; D009479:Neuropeptides / Q000494:pharmacology*; D018696:Neuroprotective Agents / Q000494:pharmacology; D009498:Neurotoxins / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D015427:Reperfusion Injury / Q000378:metabolism / Q000517:prevention & control*; D012164:Retinal Diseases / Q000378:metabolism / Q000517:prevention & control*; D055351:Retinal Neurons / Q000187:drug effects*; D013111:Spider Venoms / Q000494:pharmacology*
chemical_list: D002121:Calcium Channel Blockers; D009479:Neuropeptides; D018696:Neuroprotective Agents; D009498:Neurotoxins; D013111:Spider Venoms; C098736:Tx3 neurotoxin; D018698:Glutamic Acid